March 06 2012
Viktor Klang
We’ve just released Akka 2.0 – a revolutionary step in programming for concurrency, fault-tolerance and scalability. Download it here.
Building on the experiences from the Akka 1 series, we take Akka to the next level— resilience by default, scale up and out by configuration, extensibility by design and with a smaller footprint.
A lot of effort has gone into this release, and it’s not just a version bump, it’s truly worthy of the name “Akka 2.0”. We’d like to take the opportunity to thank all of the excellent people that have made this release possible, to Jonas, to all committers, to all users and to the excellent Scala and Java ecosystems!
Highlights of Akka 2.0
Stats
700 tickets closed!
Code changes compared to Akka 1.3.1:
1020 files changed
98683 insertions(+)
57415 deletions(-)
Also including over 300 pages of reference documentation, and tons of ScalaDoc, available at http://doc.akka.io/docs/akka/2.0/.
Use the Akka Migration package to aid in migrating 1.3 code to 2.0.
Actors
Distributable by design and asynchronous at the core
ActorSystems lets you run multiple applications in isolation
Props are immutable configuration for Actor instances
ActorPaths makes it dead easy to address Actors
Enforced parental supervision gives you Error Kernel design for free
DeathWatch makes it possible to observe termination of Actors
Routers unify what was ActorPools with LoadBalancers to form a flexible, extensible and transparent entity which quacks like an ActorRef
Stash, an API made by Phillip Haller to do conditional receives
Extensions enable you to augment ActorSystems
Scale up and out through configuration
API unification and simplification
Excellent performance, up to 20 million msg/second on a single machine, see the blog article
Slimmer footprint gives you around 2.7 million Actors per GB of memory
Dispatchers
Dispatchers are now configured in the configuration file and not the code, for easy tuning of deployed applications
Dispatcher was previously known as ExecutorBasedEventDrivenDispatcher
BalancingDispatcher was previously known as ExecutorBasedEventDrivenWorkStealingDispatcher, is now work-sharing and you can configure which mailbox type should be used
PinnedDispatcher was previously known as ThreadBasedDispatcher
Create your own Dispatchers or MessageQueues (mailbox backing storage) and hook in through config
Many different MessageQueues: Priority, Bounded, Durable (ZooKeeper, Beanstalk, File, Redis, Mongo)
Remoting
Completely transparent in user code
Pluggable transports, ships with a scalable Netty implementation
Create actors remotely using configuration or in code
TypedActors
Completely new implementation built on top of JDK Proxies
0 external dependencies, so now in akka-actor
Built as an Akka Extension
Futures & Promises
Harmonized API with SIP-14 (big props to the EPFL team: Philipp Haller, Aleksandar Prokopec, Heather Miller and Vojin Jovanovic)
Smaller footprint
Completely non-blocking implementation
Akka STM
Now uses ScalaSTM
Transactors
Agents
EventBus
A simple and easy to use API for Publish/Subscribe
Config
Now using HOCON, extremely powerful and easy to use
Big props to Havoc Pennington
Serialization
Highly pluggable system for serializing objects
Mappings go into configuration, no need to mix business logic and marshalling
Built as an Akka Extension
Patterns
“Ask/?” is now a Pattern — for Scala add import akka.pattern.ask, for Java use akka.pattern.Patterns.ask().
gracefulStop
pipeTo
ExecutionContext
One abstraction for asynchronous execution of logic
?mq
An API for using Akka with ?mq
Huge thanks to Karim Osman and Ivan Porto Carrero
Built as an Akka Extension
Brand new website, still at http://akka.io, huge thanks to Heather Miller for her outstanding work
Upcoming Releases
Things that will be released within the coming months:
Akka Camel 2.0, codename “Alpakka”, with the excellent work of Raymond Roestenburg and Piotr Gabryanczyk
Akka AMQP 2.0, with the excellent work of John Stanford
Akka Spring 2.0, with the excellent help of Josh Long
Useful Links
Akka Maven repository: http://repo.akka.io/releases
Akka binary distribution: http://akka.io/downloads
Akka 2.0 documentation: http://doc.akka.io/docs/akka/2.0/
Issue tracker: http://www.assembla.com/spaces/akka/
Akka mailing list: https://groups.google.com/group/akka-user
Akka is released under the Apache V2 license.
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